Floatable structure and method of operating same



1967 MASASUKE KAWASAKi 3,306,052

FLOATABLE STRUCTURE AND METHOD OF OPERATING SAME 5 Sheets-Sheet 1 FiledAug. 26, 1963 A Masai/n49 flowarah INVENTOR. MW b By gal .m

ATTO/P/VEVJ 1967 MASASUKE KAWASAKI 3,396,052

FLOATABLE STRUCTURE AND METHOD OF OPERATING SAME Filed Aug. 26, 1963 5Sheets-Sheet 2 M010: 0/46 //a WO'J 0h INVENTOR.

2 1967 MASASUKE KAWASAKI 3,306,052

FLOATABLE STRUCTURE AND METHOD OF OPERATING SAME NVENT R 5 Sheets-Sheet3 Filed Aug. 26, 1963 Feb 1967 MASASUKE KAWASAK! 3,306,052

FLOATABLE STRUCTURE AND METHOD OF OPERATING SAME Filed Aug. 26, 1963 5Sheets-Sheet 4 Mar 0: aka flan/cw 0/40 INVENTOR.

1967 MASASUKE KAWASAKI 3,

FLOATABLE STRUCTURE AND METHOD OF OPERATING SAME Filed Aug. 26, 196357001455 POI/770 5 Sheets-Sheet 5 McrJaJuA e /(0W0J0%/ INVENTOR. d 0mman LA BY g P.

ATTOKF/VEVJ United States Patent Oil-ice 3,36,,fl52 Patented Feb. 28,1957 3,306,052 FLQATAELE STRUCTURE AND METHOD OF OPERATING SAMEMasasulre Kawasaki, Slideil, La., assignor, by mesne assigmeuts, toEireeto Corporation, Slideli, 1.21., a corporation of Texas Filed Aug.26, 1963, Ser. No. 304,590 15 Claims. (Cl. 61--46.5)

The present invention relates generally to floating bargeplatforms foruse in marine operations to provide a stable platform with relation tothe floor of the body of water on which the device is to operate. Morespecifically, the present invention relates to a barge-platform which isdesigned to float when it is not firmly fixed in location for drilling.

Prior to the present invention much of the offshore drilling for oil andgas has been accomplished from platforms which had legs that telescopeddownwardly to the floor of the body of water or from platforms whichhave been erected on piling driven into the ocean floor. These priorstructures have had vertically extending support legs. Such priorstructures have had disadvantages in that they either had to beconstructed on the drilling site or if they were of the floatingplatform type they have been extremely bulky and difficult to tow to thedesired location, subject to overturning during movement to the desiredlocation, and they have required extensive equipment for setting theplatform on the ocean floor. Therefore, the primary object of thepresent invention is to provide a floating platform barge which isself-erecting and provided with support legs which extend downwardly andoutwardly for stability of the platform when anchored.

Another object of the present invention is to provide a floatingplatform in which most of the structure is relatively close to the waterwhen in towing position. A further object of the present invention is toprovide a floating drilling platform for marine operation having hingedlegs which can be actuated into drilling position by adding ballast tothe compartments in the legs. Another object of the present invention isto provide a floating platform for drilling which may be erected inposition for drilling by shifting ballast within the structure. A stillfurther object of the present invention is to provide a marine drillingplatform having downwardly and outwardly extending legs adapted to reston the floor of the body of water in which the platform is desired to bepositioned. Still another object of the present invention is to providea marine drilling platform with hinged legs adaptable for positioning ata variety of angles extending downwardly and outwardly from theplatform.

Another object of the present invention is to provide a barge platformhaving legs which may be ballasted wherein the legs are hydrostaticallystable at an inclination during ballasting and de-ballasting of thestructure to provide stability of the structure as a whole.

Another object of the present invention is to provide a barge platformhaving a plurality of legs two of which rotate from a parallel towingposition for floating to an inclined position having an angle ofdivergence therebetween and such rotation is caused by a controlledballasting of compartments in the legs.

A further object of the present invention is to provide a marineplatform barge having buoyant legs which may be pivoted into adownwardly and outwardly extending position by ballasting of the legsand de-ballasting of the platform.

These and other objects of the present invention are more fullydescribed in respect to the drawings wherein:

FIGURE 1 is a perspective view of the platform of the present inventionwith the legs down.

FIGURE 2 is a side elevation view of the platform of the presentinvention in floating position or towing position and with the legs upand illustrating such position with relation to the water level.

FIGURE 3 is a side elevation view of the platform of the presentinvention with the legs in the downward position and illustrating thefloating of the platform in this position with relation to the Waterlevel.

FIGURE 4 is another side elevation of the platform of the presentinvention in position on the floor of the body of water and illustratingthe position with relation to the water level.

FIGURE 5 is a detail side elevation view of the platform of the presentinvention in floating position with the legs up.

FIGURE 6 is a partial sectional View taken along line 6-6 in FIGURE 5.

FIGURE 7 is a schematic view of one leg illustrating the compartments,piping, valving and pumps contained within the leg.

FIGURE 8 is a schematic illustration of the platform barge of thepresent invention having an inclined pivot of the rear legs and showingthe upper position of the legs in solid lines and the lower position ofthe legs in dashed lines.

As shown in FIGURE 1, platform 1 is supported by rear legs 2 and 3 andby front legs 4 and 5. Drilling tower 6 is positioned on drillingplatform 7 which is fixed- 1y secured to the front edge of platform 1.Platform 1 may be of any suitable construction, but the preferred formshould be compartmented and provided with suitable ballasting anddeballasting pumps and controls for the reasons hereinafter more fullyexplained. Rear legs 2 and 3 are suitably connected by horizontal bracesS and 9 and by cross braces 10 and 11. Each of legs 2, 3, 4 and 5 iscomposed of two tubular sections (12 and 13, 14 and 15, 16 and 17, and18 and 19 respectively) joined at their outer extremities by welding toform each leg, by pivot arms 20, 21, 22 and 23 respectively between eachof the respective tubular sections of the legs and by braces 24, 25, 26and 27 respectively as shown. As best shown in FIGURE 6, tubularsections 17 and 19 of front legs 4 and 5 are joined together at theirinner extremities and are secured to platform 1 by pivot 28. If it isdesired that legs 4 and 5 move independently of each other for reasonshereinafter more fully explained, then tubular sections 17 and 19 shoudnot be joined as shown in FIG- URE 6, but should be formed to allowmovement of one with respect to the other. It should be noted that legs4 and 5 are not joined to each other by bracing as are legs 2 and 3.Suitable bracing may be used if tubular sections 17 and 19 are to bejoined and if such bracing does not interfere with the particular marineoperation for which the device is to be used. When the device is to beused for drilling, care must be taken in bracing legs 4 and 5 together,particularly sections 17 and 13, since such bracing might, in thepositions to which the legs are lowered to support platform 1, interferewith the drilling operations. Pivot 28 comprises pintle 29 extendingthrough the joined portions of sections 17 and 19, through lugs 30 whichdepend from the lower surface of platform 1 and through arms 22 and 23whereby legs 4 and 5 are pivotally secured to platform 1.

Rear legs 2 and 3 are also pivotally secured to the lower surface ofplatform 1 by pivots 31 and 32 respectively. Pivot 31 includes pintle 33extending through tubular section 13 of leg 2, through lugs 34 dependingfrom platform 1 and through arm 20. Pivot 32 includes pintle 35extending through tubular section 15 of leg 3, through lugs 36 dependingfrom platform 1 and through arm 21.

Bolting plate 37 is secured as by welding to the inner nd of section 12of leg 2 and is designed to pass through lot 38 in platform 1 when leg 2is being lowered. Sim-iirly section 14 of leg 3 is provided with boltingplate 39 lhlCh is received in slot 46, section 16 of leg 4 is proidedwith bolting plate 41 which is received in slot 42 nd section 18 of leg5 is provided with a similar bolt- Jg plate (not shown) which isreceived in slot 43. The olting plate for section 18 of leg 5 is notshown because is hidden in all of the drawings behind the other porionsof the structure, but is of similar construction to iolting plate 41except that it is reversed. Belting plates '7, 39, 41 and the boltingplate for leg 5 are all provided vith a plurality of holes as shown forreceiving suitable tolting at any desired position of the legs to lockthe iosition of the legs.

Legs 2 and 4 are provided with second bolting plates 37a and 41a securedto sections 13 and 17 respectively, .s best shown in FIGURE 1, and legs3 and 5 are proided with similar bolting plates (not shown). Such secndbolting plates are provided to lock the legs in their owing position.

The leg shown in FIGURE 7 is typical of the interior :onstruction of allof the legs of the present invention. or purposes of clarity it isidentified as leg 2. The outer uncture of sections 12 and 13 is formedinto compartnent 44 by welding partition 45 into section 12 and parition46 into section 13. Partitions 47, 48 and 49 are velded into section 12forming compartments 5t), 51, 52 md 53. Partitions 54, 55 and 56 arewelded into section l3 forming compartments 57, 58, 59 and 60. The outer:nd of leg 2 is closed by plate 61 which is welded therein to completecompartment 44. It should be noted that he position of plate 61 is suchthat it is designed to rest 7n the bottom of the body of water in whichplatform l is to be located and has the proper angle with respect 0 leg2 so that it will be substantially horizontal when eg 2 is positioned inits supporting position. Also, all )f the partitions in sections 12 and13 should be completely seal-welded, thereby forming Watertightcompartnents to prevent leakage of ballast between compartments.

Pump 62 is positioned within compartment and is provided with inlet 63having valve 64 therein to control the fiow of water to pump 62. Pump 62is shown to be powered by motor 65. It is preferred that motor 65 beelectric for simplicity of control. The wiring and switches controllingmotor 65 are not shown but are well known and any suitable controlsystem may be used without departing from the principles of the presentinvention. Inlet 63 is connected to a water source which is to be usedas ballast. Obviously, the body of water in which platform 1 is to belocated is usually the best source of water for ballast unless the watercontains such corrosive compounds as would make the ballast system(hereinafter more fully described) inoperative. In such event, asuitable source of water or other liquid ballast should be provided. Theballast system is designed to utilize normal sea water, and care istaken in the selection of materials for the pumps, valving and linesthat normal sea water does not cause such corrosion as would render theballast system inoperative.

Pump discharge 66 extends from pump 62 and acts as a manifold to valves67, 68 and 69. Line 70 connects from valve 67 into compartment 59, line71 connects from valve 68 into compartment 58 and line 72 connects fromvalve 69 into compartment 57. Vent lines 73, 74 and 75 are provided fromcompartments 57, 58 and 59 respectively. Discharge lines 76, 77 and 78extend from compartments 57, 5S and 59 respectively to valves 7?, 80 and81 respectively. Manifold 81a extends from valves 79, 80 and 81 to theinlet of pump 82. Control rod 33 is shown extending from compartment 60to valve 79 and is illustrative of the remote control provided forvalves 79, 80 and 81. Any suitable remote control may be provided tocontrol the valves used in the ballasting system of the presentinvention without departing from the invention such as providing thevalves with electric actuators and controlling the valves electrically.

Pump 82 is powered by motor 84 which is of a suitable type for remotecontrol. Pump discharge line 35 extends upwardly through section 12 andout of compartment 53 and is controlled by valve 36. The water beingused for ballast when discharged through line 85 will be discharged intothe body of water in which platform 1 is located. Unless sufficientreserve buoyancy is provided in the structure of the present invention,ballast liquid should not be stored in the structure when it isdischarged from the legs even though it is to be separately storedbecause of the unsuitability of the water in which the structure islocated.

However, as hereinafter more fully explained, ballast is preferred to bestored in the compartments of the platform 1 and then pumped by asuitable pump 201 into the legs and returned from the legs to assist inthe control of the positioning of the legs with respect to platform 1.

Discharge lines 87, 88 and 89 extend from compartments 5t 51 and 52respectively to valves 99, 91 and 92 respectively. Manifold 3 extendsfrom valves 90, 91 and 92 to the inlet of pump 82. Control rod 94 orother suitable control device extends from compartment 53 to valves 90,91 and 92. Vent lines 95, 96 and 7 extend from compartments 50, 51 and52 respectively to the exterior of compartment 53 to provide suitableventing of the chambers during the filling or emptying of the respectivecompartments.

A filling system for compartments 50, 51 and 52 is not shown in FIGURE 7but is contemplated. It is pre ferred that pump 62 be used for theballasting of com partments 50, 51 and 52 and either additional valvesshould be provided on pump discharge 66 to direct the ballast waterindividually to compartments 50, 51 and 52, or a separate filling pumpand valving similar to that shown in compartment 60 should be providedin compartment 53.

In the preferred form of the present invention, each of the compartments50, 51, 52, 57, 53 and 59 should be connected to the filling anddischarge of the ballast system so that they may be individuallycontrolled. It is possible to modify such a ballast system whereby thefilling and discharge of compartments is accomplished with a single setof controls and pumps merely by interconnecting the compartments, i.e.,connecting compartment 50 to compartment 57, connecting compartment 51to compartment 58, and connecting compartment 52 to compartment 59 butcare must be taken with the design of such a system to assure that theposition of the legs may be accurately controlled by the ballasting anddeballasting. Individual control of the ballasting of each of thecompartments is preferred. It is also within the scope of the presentinvention to provide individual ballasting of compartment 44 withsuitable controls for filling, discharge and venting, but this is notshown in order that the control system is clearly illustrated withregard to the other compartments. It should be clearly understood thatbecause of the extremely large sizes involved in the tubular sections ofthe respective legs that the enclosing of the valves, pump and motorwithin compartment 44 would iequire a relatively small amount of spacewith respect to the actual size of compartment 44. Alternately,compartment 44 may be filled with ballast water if the valves, pump andthe motor are of such construction that they will operate properly whenthey are submerged in ballast water within compartment 44.

Prime concern in ballast and deballasting is stability of the barge.Direct flooding of the compartments in the legs through sea chests orbypassing pumps should not be used. Such direct flooding will leave airin the compartment exposed to additional pressure due to depth below thewater surface and thus subject to volumechanges beyond human control andtherefore will lead to erratic control of ballasting or deballastingwhich could result in upsetting or severe tilting of the barge.

Another method for ballasting and deballasting is to control the ballastwater in the platform 1. As previously mentioned the platform 1 isconstructed to contain ballast. Referring to FIGURE 2, the platform 1could be heavily loaded with ballast water. At site the platform 1 ismade lighter by deballasting with pump 201 and suitable piping in asimilar fashion as previously explained for the legs. Then the platform1 will emerge out of water while the legs are being lowered into water.The process should be continued until the legs reach desired depth. Tobe moved from the site the platform should be ballasted after the legsare loosed from bottom of the sea and the bolting plates 37, 39, 41,etc., are unbolted.

This method of ballasting and deballasting the platform will provide abetter control. However, if such method is used, the whole structurewould normally be larger than otherwise contemplated. It is preferredthat a compromise of the two methods will be beneficial in actualapplication depending upon the other limitations such as depth and rangeof water to be covered, dead weight to be carried, and limitation ofwater channel.

Stability of tubular members submerged in water is a delicate balance asmay be readily understood by adding a small amount of water to anordinary pop bottle. The bottle will not float at an inclined angle butwill immediately take a substantially vertical position in the water.

For positive control, each leg is made up of two tubular columns formedin V-shape. Such leg structure also provides easy, positive and safecontrol, and also, as a byproduct, the necessary strength. Each leg mustbe stable by itself within the surface of its rotation, even if all thepins and bolts are loosened. As well known in naval architecture, thedesign and operation will be such as to keep the GM of each leg positiveat all times. The V-shape indicated above which keeps a wide water planebetween the ballasted compartment and the compartment full of air, isthe preferred design to accomplish the above.

Positive GM as used herein indicates that the vessel considered isstable, i.e., that center of gravity with or without ballast should bebelow the metacenter at corresponding loads assumed at the hingeresulting from the support of platform 1.

As shown in FIGURE 8 the mounting of the rear legs 2 and 3 on aninclined pivot rather than the horizontal pivots 31 and 32 shown in theother figures can position legs 2 and 3 in parallel relationship to eachother when they are in towing position and still provide a substantialangle of divergence when legs 2 and 3 are in the submerged or supportposition. The inclination of these pivots is shown to be the anglesdesignated a in FIG- URE 8. These two positions establish a plane inwhich the legs rotate and the pivot will extend perpendicular to suchplane of rotation. This pivot is easily established by proper placementof the legs below platform 1 and drilling such legs and the pintlereceiving lugs to receive a pintle so that the centerline of the pintlecoincides with the desired pivot.

The placement of the device of the present invention is clearlyexplained with reference to FIGURES 2, 3 and 4. FIGURE 2 shows platform1 and legs 2, 3, 4 and 5 in the towing position, floating on the watersurface 98. In this position the structure may be towed to the locationwhere it is to be set. If considerable distances are involved in thetowing of the floating structure to the desired location, it iscontemplated that pivots 31 and 32 may be inclined to provide thedesired spread of legs 2 and 3 when in the down position and to allowlegs 2 and 3 to assume substantially parallel relationship to each otherwhen in the up or towing position as is schematically shown in FIGURE 8and hereinbefore de- 5 scribed. When such structure configuration is tobe provided, then braces 3, 9, 10 and 11 will have to be eliminated andbolting plates 37 and 39 will have to be sloped to enter slots 38 and 40during the movement of legs 2 and 3.

With the legs positioned as shown in FIGURE 2, water ballast is added tothe outer compartments of legs 2, 3, 4 and 5 simultaneously from thecompartments in platform 1 after unbolting the respective second boltingplates. The addition of water ballast to the leg compartments from theplatform compartments will change the center of gravity of the legsoutwardly while the center of mass through the buoyancy force acts isnot changed. This shifting of the center of gravity outwardly will causethe legs to settle at their outer ends into the water and platform 1will be raised upwardly from surface 98. If ballast is from a sourceother than platform 1, the structure as a whole will still displacesufficient water to remain floating in the water but will have morestructure submerged than before ballast is added. The movement of thelegs due to ballasting will continue until they reach the positionillustrated in FIGURE 3.

Care should be taken and mechanical stops (not shown) provided ifnecessary to prevent the legs from being ballasted to a point, hereintermed critical position, where the direction of righting moment isreversed. If any of the legs are allowed to reach such point thendeballasting of the leg and ballasting of platform 1 might not allow theleg to be rotated into its upper position. By maintaining the angle ofthe legs with respect to the critical position below their respectivepivots, proper return of the legs is assured solely by deballasting ofthe legs, by ballasting platform 1 and by both.

It should be noted that allowing the legs to assume the criticalposition below the pivot connections to platform 1 would result ininstability of the structure and could result in a major accident duringthe deballasting of the legs since their upward movement could berestricted until they move away from their vertical position. If suchmovement is prevented until substantial deballasting has occurred thenthe forces due to buoyance of the legs would be tremendous as soon asthe legs moved from the vertical position. At this point all of the legsare in the down position, and are locked in position by bolting throughthe bolting plates into the platform 1. It should be noted that platform1 is substantially above water surface 98 and that the lower ends of thelegs are still above floor 99. At this point the structure is said tohave a reserve buoyancy, that is, additional ballast water must be addedto position the legs of the structure on floor 99 as shown in FIGURE 4.This further ballasting is readily accomplished with the ballastingsystem.

Extreme care should be taken in the filling of the compartments in thelegs with water ballast that platform 1 remains in a substantiallyhorizontal position and that the legs are ballasted uniformly. Thisballasting should be controlled from a central control (not shown)maintained on platform 1, and may be accomplished either manually bycontrol of the pumps and valves or automatically by controls which arewell known, to maintain the horizontal position of platform 1 during theballasting of the legs.

Normally the device of the present invention will be designed to havelegs of proper length and size so that the structure will have thedesired reserve buoyancy for the depth of water in which the device isto 'be located. In the event that the water is relatively shallow incomparison to the length of the legs, then it is contemplated that thelegs will be ballasted to a position less than the down position shownin FIGURES l, 3 and 4. The legs will then be locked in such positionwhile the structure still has some reserve buoyancy, i.e., the legs arenot touching the bottom 99. Such locking is accomplished by boltingthrough the respective bolting plates into platform 1. With the legssecured in such position, additional ballast is added and the wholestructure will 7 lescend in the water until the legs rest firmly onbottom 9. It is further contemplated by the present invention hat thedesired location may not have a bottom 99 which completely level, andtherefore one or more of the legs nay be extended to different downpositions to accomnodate such unevenness of bottom 99. Legs 4 and 5 vill'be at the same position as long as sections 17 and [9 are joined, andlegs 2 and 3 will be at the same posiion unless braces 8, 9, and 11 areomitted. If it s desired that legs 4 and 5 descend to different levelshen they should not be joined as shown in the drawing.

t is further contemplated by the present invention hat the location ofthe device may be in water having ufiicient depth that the legs will notset on the bottom, tl'ld therefore it is suggested that anchors havingfloats be )rovided to secure the structure in the desired location 11 afloating condition. Such anchor and float devices or fixing the desiredlocation of a floating structure are vell known, and therefore are notillustrated in the lrawings.

When it is desired to relocate the structure of the :resent invention,the discharge and shifting of ballast s accomplished as hereinafter morefully explained. The lischar-ge of water ballast initially should returnthe .tructure to its condition of reserve buoyancy which is llustratedin FIGURE 3. At this point the bolting of he respective bolting platesinto platform 1 should be lnbolted and then the discharge or shifting ofwater )allast continued until the structure is positioned in its owingposition as illustrated in FIGURE 2. With the egs all in up position,they should be locked in place y bolting through their respective secondbolting plates nto platform 1. The movement of the legs can easily )6accomplished from one position to the other solely y the addition ordischarge of Water ballast in the comartments contained in the tubularsections of the legs. t is contemplated, however, that in cases wheresufiicient eserve buoyancy is not available because of the shallowlessof the location, that additional mechanical means nay be provided forthe rotation of the legs into their )referred down position whereby thedesired reserve moyancy of the structure is maintained. Also, it may belesirable to have such mechanical means for movement )f the legs tomaintain their position during the periods :f bolting and un'bolting oftheir respective bolting plates 0 platform 1. Suitable winch, pulley andWire ropes or )neumatic or hydraulic actuators are examples of themechanical means contemplated by the present invention or assisting inthe positioning of the legs. Such mechancal means should be capable ofmoving the legs without he assistance of ballasting and deballasting inthe event if failure of the ballasting system.

The structure of the present invention will be contructed in differentsizes, but because of the flexibility )f design and the variablepositioning of the legs it is :ontemplated that, for example, a singlestructure will he built to accommodate water depths from 150 to 250 eet.This flexibility of the structure will allow a maxinum range ofapplicability for water depths for each ize structure.

Also in the design of a barge platform in accordance vith the presentinvention consideration must be given 0 the maximum wave height to whichthe structure will ie exposed when set on the ocean floor. Maximum waveieights are normally assumed to be from 30 to 50 feet n normal offshorelocations. Therefore, for any given lepth when the structure is to reston the ocean floor, he minimum length of legs must be at least equal tothe naximum depth of the water at the location plus the lesired heightof the hinges above the waters surface )lllS an added length suificientto enable the legs to be n contact with the ocean floor without reachinga vertical iosition plus an added length of at least 30 to 50 feet 0 beequal to the expected maximum wave height.

The preferred form of the legs is tubular as shown,

however, the legs may be constructed from structural steel and beprovided with reservoirs integral with each leg and the reservoirs musthave sufficient buoyancy to support the legs, the platform and thepayload and to lift the whole structure so that the platform is at least30 feet above the surface of the water. Such reservoirs should also beprovided with pump and controls for ballasting and de'ballastings aspreviously described herein relating to such pump and controls in thelegs shown in the drawings.

The operation of the ballasting system is best understood in referenceto FIGURE 7. With all compart ments empty the legs will be positioned asshown in FIGURES 2 and 5. Ballasting is commenced by opening valve 64and supplying water to inlet 63. With valve 69 open, motor is startedand pump 62 will pump water ballast through line 66, valve 69 and line72 into compartment 57. It is suggested that if tubular section 12 isprovided with a separate filling system that its pump be started at thesame time as pump 62 and that compartment 50 be filled at the same timeas compartment 57. If compartment 44 is to receive ballast, then it issuggested that it be filled first to provide the maximum turning momenton leg 2 to more quickly rotate leg 2 into its down position. Aspreviously mentioned, the ballasting of all legs should proceedsimultaneously and platform 1 should be maintained in a substantiallyhorizontal position. When the compartments which are being filled firstare completely full of water ballast, the next compartment to be filledshould be the compartment which is the farthest horizontal distance fromplatform 1 and that compartment which will provide the maximum turningmoment for the rotation of the leg. \/Vhen the leg has been partiallyballasted by filling compartment 44, it is suggested that compartment 50be filled before compartment 57 since it will have a greater effect onthe movement of the leg into its down position. The order of filling ofthe compartments, assuming that they are all independently controlled,will proceed as follows: Compartment 44 should be filled first, thencompartment 50, then compartment 57, then compartment 51, and, with theleg nearing its down position, compartment 52 should be filled toprovide the final turning of the leg into its desired position.Compartments 58 and 59 may be filled to overcome the reserve buoyancyafter the legs have been locked in their desired position. It issuggested that when the structure is fixed in position on the bottom,that all compartments be completely filled to overcome any buoyancy andthereby provide a stable position for the structure which will not beaffected by movement of the water, either by waves at the surface or bycurrents.

During the ballasting, when compartment 57 has been filled and it isdesired to commence filling of compartment 58, valve 69 should be closedand valve 68 opened. The completing of the filling of compartment 57 maybe determined by the observing of water being discharged through ventline 73, or the desired amount of water ballast may be metered, and,when sufiicient ballasting of compartment 57 has been accomplished, thenthe ballasting of the next compartment may be commenced by the changingof the valves 67, 68 and 69.

Vent lines 73, 74, 75, 95, 96 and 97 are provided to all compartmentswhich are to receive water ballast to prevent the building up ofpressure within the compartments during filling and the creating of avacuum in the compartments during discharge of water ballast. It ispreferred that each compartment be filled less than completely full toprevent the filling of the vent lines. With the vent lines full, it isnoted that the interior of the compartment would always be subject to aslightly higher pressure than the exterior of each compartment due tothe slight height of the vent lines outlet above the level of the water.Filling of the vent lines will cause a pressure differential between acompletely full compartment and its adjoining compartment if theadjoining compartment is not completely full. To avoid such pressuredifferentials and to always assure that the pressure in the compartmentsis lower than the water pressure surrounding the compartment, it ispreferred that the vent lines not be filled and that the lower portionsof the legs be desi ned to withstand the exterior pressure of the waterat the depth to which they will be exposed.

The discharge of water ballast from the legs should be commenced byopening valve 86 and opening valve 81 by actuating control rod 83. Withvalve 81 and valve 85 open, motor 84 should be started and water will bepumped from compartment 60 through line 78, valve 81, manifold 81a, pump82, line 85 and valve 86 to discharge normally into the compartments ofplatform 1 or in the body of water in which the structure is located.When compartment 64 is empty, valve 81 should be closed and valve 8%opened to proceed with the emptying of compartment 59. It should benoted that the compartments in tubular section 12 may be emptied ofwater ballast at the same time as the compartments in tubular section 13are being emptied by the opening of valve 90, 91 or 92, since bothmanifold 81a and manifold 93 are connected directly into the inlet ofpump 82. Sufiicient ballast should be removed until the structure hasreturned to its position of reserve buoyancy illustrated in FIGURE 3,then the legs should be unbolted from platform 1, and thereafter thedischarge of ballast should proceed until all of the legs have returnedto their towing position. Care should be taken in the discharge ofballast to assure that platform 1 remains substantially level. This maybe done through a manual control or by automatic control as hereinbeforesuggested with relation to adding ballast to the legs.

From the foregoing it can be seen that the present invention provides aplatform for offshore locations which will float for towing to locationand Which will position itself for drilling or other application by theballasting of compartments in its legs. The ballasting of the legs andde-ballasting of the platform will cause the legs of the device torotate from a substantially horizontal or floating position into adownwardly and outwardly extending position, and further ballastingafter locking the legs in position will set the device on the bottom inthe desired location. The present invention provides a floatableplatform for marine operations such as drilling having downwardly andoutwardly extending legs engaging the floor of the body of water inwhich the device is to be located wherein the leg positions providegreat flexibility of positioning and stability for the platform whichthey support.

The present invention provides a floatable barge platform hingedlyconnected to buoyant legs which are forced down whereby the platform inraised above the waters surface. \Vhen the legs are forced down to theproper position they are set so as to prevent them from turning any morearound the hinges and the whole system may then be brought to rest onthe oceans floor by ballasting.

The invention further provides a barge platform structure capable ofbeing ballasted to any desired position and deballasted to return to itsunballasted position. Thus, the position of the structure is controlledby the amount of ballast and by controlling the ballast stability ofposition is maintained. Also, this invention provides a floatable bargeplatform having a plurality of legs at least two of which pivot from asubstantially parallel towing position to a divergent submergedposition.

The foregoing disclosure and description of the invention isillustrative and explanatory thereof, and various changes in the method,as well as in the details of the illustrated construction, may be madewithin the scope of the appended claims without departing from thespirit of the invention.

What is claimed is:

1. A platform structure for offshore location comprisa platform, I

a plurality of V-shaped legs,

each leg including two tubular sections jointed together at one end andsecured together at its other end by an arm to form the V-shaped legs,

each of said legs being pivotally secured to said platform at the armend of one of said tubular sections,

each of said tubular sections being compartmented to receive ballast,

a bolting plate secured to the arm end of the tubular section of eachleg opposite the tubular section which is pivotally secured to saidplatform for securing said leg to said platform, and

means for ballasting and deballasting the compartments in said tubularsections to pivot said legs with respect to said platform.

2. A platform structure according to claim 1 wherein each of said legsincludes a reserve buoyancy to lift said platform when said legs havebeen pivoted by ballasting into a supporting relation below saidplatform.

3. In a method of operating a floating platform barge having a pluralityof buoyant legs, said buoyant legs being characterized by having alength greater than the depth of the water in which the floatingplatform barge is to be used, each leg being pivotally secured to saidplatform, starting with the legs extending substantially horizontallywith respect to said platform, the steps of ballasting said legs to movesaid legs downward in the water to a position extending downwardly andoutwardly from said platform,

the downward movement of said legs in the water responsive to saidballasting lifting said platform above the water, and

locking said legs to said platform.

4. In the method as set forth in claim 3, the additional step ofstopping the pivoting movement of said legs with respect to saidplatform before said legs reach a substantially vertical position belowtheir respective pivotal connections to said platform.

5. In the method as set forth in claim 3 wherein said ballasting of thelegs includes the step of shifting ballast from said platform to theouter ends of said legs to reduce the weight of said platform.

6. In the method as set forth in claim 3 wherein the downward movementof said legs in the water responsive to said ballasting and the combinedreserve buoyancy of said legs when pivoted to a final supportingposition lifts said platform above the water.

7. In a method of operating a floating platform barge having a pluralityof buoyant legs, said buoyant legs being characterized by having alength greater than the depth of the water in which the floatingplatform barge is to be used, each leg being pivotally secured to saidplatform, starting with the legs releasably locked to the platform andextending downwardly and outwardly below the platform and supporting theplatform above the water, the steps of releasing the locked connectionbetween the legs and the platform, and

deballasting the legs to pivotally move the legs upward in the water toa substantially horizontal position,

the movement of the legs upwardly in the water responsive to saiddeballasting progressively decreasing the support of the platform by thelegs to lower the platform to the surface of the water.

8. A floatable structure for offshore location, com

prising a platform,

a plurality of legs, each leg being pivotally secured at one end to saidplatform and adapted to pivot with respect to said platform,

means for admitting ballast to said legs,

means controlling the admission of ballast to said legs whereby saidlegs are pivoted from a substantially horizontal position downward inwater below said platform, said legs having sufficient reserve buoyancywhen ballasted to a position below said platform to lift said platformabove the surface of the water, and

releasable locking means securing said legs to said platform to preventpivoting of said legs with respect to said platform.

9. A floatable structure for offshore location, comprising a platform,

a plurality of legs, each leg being pivotally secured at one end to saidplatform,

means for admitting and discharging ballast to and from said legs, and

means controlling the ballasting of said legs whereby said legs arepivoted downward from a substantially horizontal towing position to aposition below 'said platform,

at least two of said legs having inclined planes of rotation, saidplanes of rotation being inclined with respect to a vertical plane andextending outwardly and downwardly below the platform with respect tosaid vertical plane whereby said two legs are substantially parallel intheir substantially horizontal towing position and diverge with respectto each other in all other positions.

10. A floatable structure for offshore location, comprising a platform,

a plurality of legs, each leg being pivotally secured at one end to saidplatform,

means for shifting ballast between said legs and said platform, andmeans controlling the shifting of ballast between said legs and saidplatform whereby said legs are adapted to be pivoted with respect withsaid platform between a substantially horizontal position and a positionwherein said legs extend downwardly and outward below said platform,said legs having sufficient reserve buoyancy to lift said platform whensaid legs are pivoted by ballasting to a position below said platform.

11. A structure according to claim 8 wherein the pressure exerted by theballast in each leg is less than the water pressure on exterior of eachleg and said legs have sufficient structural strength to withstand thepressure differential caused thereby.

12. A structure according to claim 10 wherein the combined reservebuoyancy of said legs is sufficient to lift said platform at leastthirty feet above the surface of the water when said legs are positionedbelow said platform.

13. A fioatable structure according to claim 10 wherein said platformincludes a plurality of ballast compartments,

each of said legs includes a plurality of ballast compartments, and

said controlling means controls the shifting of ballast between theballast compartments of said platform and the ballast compartments ofsaid legs.

14. A platform structure for offshore location, comprising a platform,

a plurality of legs,

each leg composed of two tubular sections joined together at one end andsecured together at its other end by an arm to form a V-shaped leg,

means pivotally securing each of said legs to said platform at the armend of one of the tubular sections of said legs,

each of said legs being compartmented to receive ballast,

means for ballasting and deballasting the compartments in said legs, and

means releasably securing the arm ends of the other tubular section ofsaid legs to said platform in at least two positions to prevent pivotingmovement of said legs with respect to said platform.

15. A platform structure for offshore location, comprising a platform,

a plurality of legs,

each leg having two tubular sections joined together at one end andsecured together at their other end by an arm,

means pivotally securing each of said legs to said platform at the armend of one of the tubular sections of said legs,

each of the legs being compartmented to receive ballast,

means for ballasting and deballasting the compartments in said legs,

said tubular sections being spaced apart at their arm ends a greaterdistance than at said joined end whereby said legs provide a positive GMat all positions of the legs with respect to said platform, and

means releasably securing the arm end of the other tubular section ofsaid legs to said platform in at least two positions to prevent pivotingmovement of said legs with respect to said platform.

References Cited by the Examiner UNITED STATES PATENTS 2,598,329 5/1952Wilson 61 46.5 2,600,761 6/1952 Halliburton 6146.5 2,608,829 9/1952Knapp 6146.5 2,622,404 12/1952 Rice 61-46.5 2,968,930 1/1961 Mangone6146.5

CHARLES E. OCONNELL, Primary Examiner.

JACOB SHAPIRO, Examiner.

1. A PLATFORM STRUCTURE FOR OFFSHORE LOCATION COMPRISING, A PLATFORM, APLURALITY OF V-SHAPED LEGS, EACH LEG INCLUDING TWO TUBULAR SECTIONSJOINTED TOGETHER AT ONE END AND SECURED TOGETHER AT ITS OTHER END BY ANARM TO FORM THE V-SHAPED LEGS, EACH OF SAID LEGS BEING PIVOTALLY SECUREDTO SAID PLATFORM AT THE ARM END OF ONE OF SAID TUBULAR SECTIONS, EACH OFSAID TUBULAR SECTIONS BEING COMPARTMENTED TO RECEIVE BALLAST, A BOLTINGPLATE SECURED TO THE ARM END OF THE TUBULAR SECTION OF EACH LEG OPPOSITETHE TUBULAR SECTION WHICH IS PIVOTALLY SECURED TO SAID PLATFORM FORSECURING SAID LEG TO SAID PLATFORM, AND MEANS FOR BALLASTING ANDDEBALLASTING THE COMPARTMENTS IN SAID TUBULAR SECTIONS TO PIVOT SAIDLEGS WITH RESPECT TO SAID PLATFORM.